Skin dressing machine

ABSTRACT

The invention disclosed relates to a machine for buffing skins or like materials which machine includes means for increasing the buffing depth either manually or automatically by advance of the skin itself, or like material, in the machine.

United States Patent [191 Repetto Dec. 3, 1974 SKIN DRESSING MACHINE [56] I References Cited 75 Inventor: Silvio Repetto, Modena, Italy UNITED STATES PATENTS Assigneez s. p A. Luigi Rizzi & Modena, 3,041,865 7/1962 Gianoglio 69/42 Italy FOREIGN PATENTS OR APPLICATIONS y 11, GU28! Britain [21] Appl. N0.: 359,276 Primary Examiner-Othell M. Simpson Attorney, Agent, or Firm-Kurt Kelman [30] Foreign Application Priority Data May 27, 1972 Italy 24968/72 [57]. ABSTRLACT a The inventlon disclosed relates to a machine for buff- [52] US Cl. 51/78 51/165 9 69/42 ing skins or like materials which machine includes [51 1 Int Cl "1324b 37/00 49/08 means for increasing the buffing depth either manually [58] Fieid "69/38 51/165 9 78 or automatically by advance of the skin itself, or like 5 material, in the machine.

5 Claims, 1 Drawing Figure l SKIN DRESSING MACHINE This invention relates to a feed through buffing machine having means for increasing the buffing depth, which means is controllable either manually or automatically by advance of the skin or like material itself in the machine.

As is well known in the art, continuous buffing machines for skins or like materials include a driven conveyor roller which is covered with elastic material such as rubber; a freely rotating retaining roller, the radial position of which, relative to the axis of the conveyor roller, is adjustable; and a driven buffing roller which is covered with an abrasive material or otherwise drives a continuous strip of abrasive material tensioned between such a roller and a tensioning or idler roller.

The skin, or like material, compressed by a retaining roller against the conveyor roller, is driven towards the buffing roller and is acted upon thereby. To enable the buffing roller to perform effectively, it has to act with appreciable pressure on the material being processed. This pressure is determined by the processing depth, which depends on the distance between the peripheries of the two rollers, on the thickness of the material being processed, and on the elasticity of the covering of the conveyor roller.

The skin or like material, during the buffing process, is not driven forward by the abrasive roller, but continues to advance with the peripheral speed of the conveyor roller. This occurs even if the speed of the buffing roller is appreciably greater than that of the conveyor roller, and is due to the fact that the skin or related material strongly adheres to the elastic covering on the conveyor roller under the pressure exerted thereon from the other two rollers.

As is also well known, when the end portion of the skin, for example, leaves the line of pressure or nip between the conveyor roller and the retaining roller, itmay happen, particularly in the case of soft skins and when using coarse-grained abrasives on the buffing roller, that the portion of skin left free turns back towards the buffing roller, and thus becomes processed on the opposite side to that required. With buffing rollers of normal dimensions, this false dressing or buffing extends over a length of some centimeters and over, the entire width of the skin, thus resulting in a considerable amount of spoilage. It has now been found that this disadvantage is eliminatedby practice of the present invention which, either manually or under automatic control, provides means which increase the working space between the conveyor roller and the buffing roller by a predetermined amount and thereby alters or reduces the pressure and hence the action of the buffing roller on the skin or like material, upon leaving the nip between the retaining and conveyor rollers.

This increase of working space between the conveyor roller and the buffing roller may be accomplished by including in a buffing machine having a conveying roller provided with rotary drive, a retaining roller freely rotatable, and a polishing or buffing abrasive roller, the further provisions in combination therewith of a rocker lever disposed for carrying the conveying roller and pivoted to move the axis of the conveying roller towards or away from the axis of the buffing roller; a hydraulic thrust means in association with the conveying roller with an adjustable hydraulic first valve, a sliding memberof the first valve being actuated by the conveying roller lever in such manner that with every movement of the conveying roller axis, there is a corresponding movement of the sliding member to supply fluid under pressure to the thrust means for restoring the conveying roller to a predetermined position.

After a desired space thickness for processing materials using the present machine isestablished, the distance between the peripheries of the conveying roller and the buffing roller tends to remain constant notwithstanding variations in the thickness of skins, for example, being processed by elements forming the present invention. Thus, by means of an oscillating lever and associated pistons and valves, it is possible to vary the space between the conveying roller and the buffing roller in a predetermined amount and thereby alter the pressure and action of the buffing roller on the skin being processed.

Although the present machine is described with special regard to skin processing, it will be appreciated that related materials including leather and leather-like artificial or simulated materials may be correspondingly processed without limitation. Also, the buffing roller may be suitably operated with an abrasive belt or by using an abrasive coating thereon in either regard with abrasiveness as desired.

By means of elements forming the present machine, a constant pressure balance tends to be provided by one or more valves relative pistons and levers which function with support of the rollers despite the thickness of the material being processed. The means for increasing the buffing depth may be either manually or automatically performed as desired.

Practice of the present invention will become more apparent by reference to the accompanying drawing which illustrates a buffing machine for skins or the like with .the usual processing rollers, i.e., a conveying roller 1, provided with a rotary drive in the direction of the arrow A, a retaining roller 2 freely rotatable, and apolishing or buffing roller 3, driven to rotate in the direc- I whereas buffing roller 3 is provided with abrasive material or otherwise drives a strip of abrasive material having suitable abrasive value, tensioned between said buffing roller 3 and an associated parallel roller, not shown.

Conveying roller 1 is carried by lever 8 which is pivoted about axis 9. At end 8a of the lever, there is provided a projection 10 having, if desired, a contact roller which rests on the free end of piston rod 11 of a hydraulic thrustor which includes piston 12 and cylinder 13, the latter being supplied with pressure fluid via pipes 14 and 15.

A first slide valve 16 is axially adjustable relative to the base of the machine by means of threaded spindle l7 movable relative to threaded collar 18 upon rotation of the threaded collar by gear 19 and hand wheel 20. The threaded collar is axially immovable relative to the base of the machine 21.

Valve 16 has sliding member 22 carrying lands 22a, 22b and urged upwardly by spring 23. The valve 16 is connected by pipe 24 to a source of pressure fluid (not shown), by pipes 25 and 26 to a discharge pipe 27, and by outlets 14a and a to supply pipes 14 and 15 respectively, the pressure fluid causing downward or upward movements of the piston 12 when applied through outlets 14a and 15a, respectively.

Sliding member 22 is urged by spring 23 into contact with an eccentric 28 carried on arm 29 which is connected to end 8b of lever 8. Arm 29 includes cylinder 30 in which piston 31 slides, the piston rod 32 of which is attached to lever 33 connected to operate with eccentric 28. Movement of one end of lever 33 is limited by stop 34 which may be secured in various positions 35 along extension arm 36 connected to arm 29.

Cylinder 30 is connected by pipes 37 and 38 to second valve 39 which is connected to a pressure source 40 and to sump 41. Second valve 39 is operated electrically by a solenoid.

The operation of the machine is as follows.

Assuming it is necessary to buff a series of skins having substantially the same thickness, the first requirement is to adjust the position of valve 16 by means of hand wheel and associated members such that valve ports 14b and 15b are blocked by lands 22a and 22b when the desired space for processing a desired depth on the series of skins is established between conveying roller 1 and buffing roller 3. In this condition, the distance between the peripheries of conveying roller 1 and buffing roller 3 tends to be kept constant even if the thickness of the skins P varies appreciably.

An increase in the thickness of skin P causes a lowering of end 8a of lever 8 in the direction of the arrow C, and a corresponding rise of the eccentric 28 connected to the other end 812 of the lever 8.

Sliding member 22 is urged by spring 23 to follow the rising movement of eccentric 28. Consequently, land 22a opens port 15b to receive fluid pressure from inlet 24 while land 22b connects port 14b to outlet 26. Pressure of the fluid through pipe 15 enters the lower end of cylinder 13 and urges piston 12 upwardly so that lever 8 moves in the direction of the arrow D. This movement lowers the eccentric 28 and sliding member 22 until both ports 15b and 14b are closed again, thus resetting the position of conveying roller 1.

When the end portion of skin P passes beyond the retaining roller nip, an operator manually, or an automatic scanner (not shown), closes a contact which energizes the solenoid valve 39. This then sends fluid under pressure from source 40 to pipe 37 and hence to the left end (with regard to the figure) of cylinder 30.

Piston 31 is displaced to the right until pivoting lever 33 comes into contact with stop 34. Such movement displaces sliding member 22 downwardly, connecting port 15b to outlet and port 14b to feed pipe 24. A downward movement of piston 12 correspondingly results and conveying roller 1 follows, while eccentric 28 is raised until it reaches a new position of equilibrium relative to sliding member 22. This new position results in an increase in the distance between conveying roller 1 and buffing roller 3 with consequent reduction of pressure on skin P. This action, therefore, avoids the turning-over of the freed end of skin P and avoids undesired processing of the wrong side of the skin. When the skin P has passed from between conveying roller 1 and buffing roller 3, either the operator or the scanner returns solenoid valve to a condition of rest (as shown) in which the right-hand end of cylinder 30 is supplied with pressure fluid and piston 21 is urged to the left-hand end into its starting position.

It will thus be apparent that either manually or automatically, the working space between the conveying roller and the buffing roller may be varied by a predetermined amount and thereby alter the pressure and hence the action of the buffing roller on the skin such that processing waste by turning-over of the freed end of skin P is avoided.

It will be understood that the foregoing description is given merely by illustration and that many variations may be made therein by those skilled in the art without departing from the scope of the present invention.

What is claimed is:

1. A machine for buffing skins, which comprises, in combination:

1. a driven skin conveying roller,

2. a retaining roller defining a nip with the conveying roller, the skin being conveyed through the nip,

3. a skin buffing roller defining an adjustable nip with the conveying roller, the skin being buffed in the adjustable nip by the buffing roller,

4. a rocker lever having two arms and mounted for pivotal movement,

a. one of the rocker lever arms supporting the conveying roller for adjusting the nip between the conveying roller and the buffing roller upon pivotal movement of the lever,

5. a hydraulically operated thrust means arranged in contact with the one rocker lever arm for effectuating the pivotal movement thereof to provide a basic nip adjustment,

6. a source of hydraulic pressure fluid and a hydraulic supply conduit means connected to the thrust means for operating the thrust means and providing the basic nip adjustment, and

7. a first valve in the hydraulic supply conduit means for controlling the supply of hydraulic pressure fluid to the thrust means, the first valve including a. a sliding member operatively associated with the other rocker lever arm and axially moved thereby upon pivotal movement of the lever in correspondence to the corresponding nip adjustment, the axial movement of the sliding valve member controlling the hydraulic pressure fluid supply to the thrust means to restore the skin conveying roller to the basic nip adjustment.

2. The skin buffing machine of claim 1, wherein the operative association of the sliding member with the other rocker lever arm comprises an eccentric in contact with the sliding member and a hydraulically operated means mounted on the other rocker lever arm for adjusting the eccentric in respect of the sliding member and thereby to move the sliding member axially whereby the basic nip adjustment may be varied.

3. The skin buffing machine of claim 2, further comprising a second hydraulic fluid supply conduit means and a second valve therein, the second conduit means being connected to the hydraulically operated sliding member adjusting means for operating the adjusting means and thereby the variation of the basic nip adjustment.

4. The skin buffing machine of claim 3, wherein the second valve is a solenoid valve.

5. The skin buffing machine of claim 2, further comprising a lever pivotal by the hydraulically operated means and carrying the eccentric, and an adjustable stop limiting the pivotal movement of the lever. 

1. A machine for buffing skins, which comprises, in combination:
 1. a driven skin conveying roller,
 2. a retaining roller defining a nip with the conveying roller, the skin being conveyed through the nip,
 3. a skin buffing roller defining an adjustable nip with the conveying roller, the skin being buffed in the adjustable nip by the buffing roller,
 4. a rocker lever having two arms and mounted for pivotal movement, a. one of the rocker lever arms supporting the conveying roller for adjusting the nip between the conveying roller and the buffing roller upon pivotal movement of the lever,
 5. a hydraulically operated thrust means arranged in contact with the one rocker lever arm for effectuating the pivotal movement thereof to provide a basic nip adjustment,
 6. a source of hydraulic pressure fluid and a hydraulic supply conduit means connected to the thrust means for operating the thrust means and providing the basic nip adjustment, and
 7. a first valve in the hydraulic supply conduit means for controlling the supply of hydraulic pressure fluid to the thrust means, the first valve including a. a sliding member operatively associated with the other rocker lever arm and axially moved thereby upon pivotal movement of the lever in correspondence to the corresponding nip adjustment, the axial movement of the sliding valve member controlling the hydraulic pressure fluid supply to the thrust means to restore the skin conveying roller to the basic nip adjustment.
 2. a retaining roller defining a nip with the conveying roller, the skin being conveyed through the nip,
 2. The skin buffing machine of claim 1, wherein the operative association of the sliding member with the other rocker lever arm comprises an eccentric in contact with the sliding member and a hydraulically operated means mounted on the other rocker lever arm for adjusting the eccentric in respect of the sliding member and thereby to move the sliding member axially whereby the basic nip adjustment may be varied.
 3. The skin buffing machine of claim 2, further comprising a second hydraulic fluid supply conduit means and a second valve therein, the second conduit means being connected to the hydraulically operated sliding member adjusting means for operating the adjusting means and thereby the variation of the basic nip adjustment.
 3. a skin buffing roller defining an adjustable nip with the conveying roller, the skin being buffed in the adjustable nip by the buffing roller,
 4. a rocker lever having two arms and mounted for pivotal movement, a. one of the rocker lever arms supporting the conveying roller for adjusting the nip between the conveying roller and the buffing roller upon pivotal movement of the lever,
 4. The skin buffing machine of claim 3, wherein the second valve is a solenoid valve.
 5. The skin buffing machine of claim 2, further comprising a lever pivotal by the hydraulically operated means and carrying the eccentric, and an adjustable stop limiting the pivotal movement of the lever.
 5. a hydraulically operated thrust means arranged in contact with the one rocker lever arm for effectuating the pivotal movement thereof to provide a basic nip adjustment,
 6. a source of hydraulic pressure fluid and a hydraulic supply conduit means connected to the thrust means for operating the thrust means and providing the basic nip adjustment, and
 7. a first valve in the hydraulic supply conduit means for controlling the supply of hydraulic pressure fluid to the thrust means, the first valve including a. a sliding member operatively associated with the other rocker lever arm and axially moved thereby upon pivotal movement of the lever in correspondence to the corresponding nip adjustment, the axial movement of the sliding valve member controlling the hydraulic pressure fluid supply to the thrust means to restore the skin conveying roller to the basic nip adjustment. 